Reed valve controlled canister

ABSTRACT

A smoking article such as a cigarette comprises a tobacco rod and a filter assembly that includes an impervious sealed canister at least partially filled with an active medium for modifying the characteristics of mainstream tobacco smoke. Placement of the active medium in the sealed canister maintains its freshness and activity level over extended periods of time. Valve structure on opposite ends of the canister have normally closed positions for sealing the active medium within the impervious canister. The valve structures also have open positions upon the application of draw upon the cigarette so that mainstream smoke generated by the tobacco rod when lighted passes through the open valve structures and the active medium within the canister. The active medium inside the canister may be activated carbon for removing selected constituents from mainstream tobacco smoke and/or flavor enhancing compositions for imparting flavors to the smoke, for example.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to the improved delivery ofadditive materials to smoking articles. More particularly, thisinvention relates to providing additive materials in sealed canistersthat are opened during use to modify the characteristics of smokingarticles such as to remove selected smoke constituents and/or add flavorto the smoke.

[0002] It is known to provide a smoking article with additive materialsto modify the characteristics of the smoking article. Additive materialstypically modify the characteristics of the smoking article by passinggases, more particularly the gaseous by-products of combustion, throughthe portion of the smoking article containing the additive material.

[0003] For example, sodium and/or calcium permanganate Ca(MnO₄)₂ orNaMnO₄ with colloidal silica deposited onto silica gel or alumina hasbeen incorporated into filter elements to reduce smoke components suchas NO, HCN, etc., as are disclosed in U.S. Pat. Nos. 3,957,059 and4,637,408, incorporated herein by reference. Menthol and otherflavorants deposited on carbon, silica, and other activated particles inthe filter section of a smoking article have been used to impart aflavor or taste to the smoking article.

[0004] One of the problems with adding additive materials to smokingarticles is that the active agents of the additive materials deactivateor volatize with time so that they do not have the desired effect at thetime of smoking. Further, flavorant materials may be extensively trappedby components of the smoking articles so that less then desired amountsare delivered to the smoker. For example, a significant amount ofmenthol is trapped on active carbon or in cellulose acetate fibers of aconventional cigarette. Adding excess additive materials to compensatefor expected loss of activity or entrapment results in inconsistentproducts because of variations in storage time prior to smoking and theconditions under which the article is smoked. The rigorous controls overproduct storage conditions and shelf life that would be required tominimize the volatility or deactivation of the active agent in theadditive material are not commercially practical.

[0005] Another problem is that some agents deactivate with theabsorption of moisture or other volatile materials during storage or canmigrate to the wrapper or embed in the filter or carrier of the smokingarticle so that they will not modify the smoke characteristics asdesired.

[0006] A problem with adding additive materials to filter portions ofsmoking articles is that the filter containing, for example, the carbonactivated particles on which menthol is conventionally deposited iscloser to the burning end of a smoking article than is desirable, thusresulting in inefficient or unsatisfactory use of or undesiredcombustion or pyrolysis of the additive.

[0007] Accordingly, there is a continuing need to provide for improvingthe effective and efficient delivery of additive materials for modifyingthe characteristics of smoking articles under widely varying storageconditions.

SUMMARY OF THE INVENTION

[0008] It is an object of this invention to provide a canister thatcontains an additive material for the modification of smoking articlesto minimize the loss or degradation in efficacy of the additive materialprior to smoking.

[0009] It is a further object of this invention to provide a canisterthat contains a smoke modifying additive material in a sealed conditionprior to smoking, and which at the time of smoking may opened so as tounseal the active agent to render it available to modify the smoke ofthe smoking article.

[0010] In accordance with the present invention, a smoking articlecomprises tobacco and a filter component that includes an impervioussealed canister at least partially filled with an active medium such asa medium for removing selected constituents from tobacco smoke and/or amedium for adding flavor, for example. The freshness and activity levelof the active medium is maintained until lighting of the smoking articleand drawing smoke therefrom. During smoking, the canister is unsealed tothereby expose the active medium therein to the mainstream tobacco smokegenerated by the smoking article.

[0011] Preferably valve structures on opposite ends of the canister eachhave a normally closed condition for sealing the active medium withinthe impervious canister. Additionally, the valve structures each have anopened condition when draw is applied to the smoking article duringsmoking. With the valve structures in their opened positions, mainstreamsmoke generated by the tobacco when lighted passes through the valvesand the active medium within the canister.

[0012] Each valve structure may comprise a reed valve having a normallyclosed condition. When vacuum is applied to these reed valves duringdrawing upon the smoking article, each reed valve is pulled or otherwisedeflected downstream which opens the valves thereby allowing mainstreamsmoke to pass into and out of the canister and through the active mediumtherein.

[0013] The active medium may comprise activated carbon for removingselected constituents from mainstream tobacco smoke. Also, other activemediums may be filled into the canister such as flavorants for impartingflavor to mainstream tobacco smoke, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Novel features and advantages of the present invention inaddition to those mentioned above will become apparent from a reading ofthe following detailed description in conjunction with the accompanyingdrawings wherein similar reference characters refer to similar parts andin which:

[0015]FIG. 1 is a side elevational view of a cigarette with animpervious sealed canister containing an active medium for modifying thecharacteristics of mainstream tobacco smoke, according to the presentinvention;

[0016]FIG. 2 is an enlarged longitudinal cross sectional view of thefilter end of the cigarette shown in FIG. 1 with the valve mechanisms onopposite ends of the canister in their normally closed condition,according to the present invention;

[0017]FIG. 3 is a right end elevational view of the filter end of thecigarette shown in FIG. 2;

[0018]FIG. 4 is a view similar to FIG. 2 but showing the valvemechanisms in their opened condition;

[0019]FIG. 5 is a right end elevational view of the filter end of thecigarette shown in FIG. 4; and

[0020]FIG. 6 is a view similar to FIGS. 2 and 4 illustrating analternate embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] Referring in more particularity to the drawings, FIG. 1illustrates a cigarette 10 comprising a tobacco rod 12 and a filterassembly 14. Both the tobacco rod and the filter assembly are surroundedby an outer wrap of paper 16. Filter assembly 14 includes an imperviouscanister 18 at least partially filled with an active medium 20. Theactive medium may comprise any desired substance for modifyingmainstream tobacco smoke, as explained more fully below. For example,activated carbon may be used to remove selected constituents from thetobacco smoke and/or flavorants may be used to impart a desired flavorto the tobacco smoke. Such flavorant enhancing substances may includethe flavored threads described in U.S. Pat. No. 4,281,671, incorporatedherein by reference.

[0022] The impervious canister 18 includes an interior compartment 24for containing the active medium 20. The compartment includes oppositeend walls 26, 28 and these walls are perforated thereby allowingmainstream smoke from tobacco rod 12 to pass through the active mediumunder certain conditions during smoking.

[0023] An upstream reed valve 30 is positioned within the canister 18slightly spaced from the end wall 26 of compartment 24. Similarly, adownstream reed valve 32 is positioned within the canister 18 slightlyspaced from end wall 28 of compartment 24. Each reed valve includes asupport plate 34 with a central opening 36. A normally closed flap 38 ispositioned directly adjacent to each support plate 34. The flap includesa live hinge line 40 about which the flap articulates. The flap 38 maybe formed by a in a U-shaped cut 42 in a disc 44 fixed in place next tosupport plate 34. Each flap has a normally closed position as shown inFIG. 2 where the flaps seal the openings 36 in the support plates 34.However, upon the application of suction generated when drawing on thefilter assembly of cigarette 10, the flaps 38 both move in a downstreamdirection thereby moving away from their associated openings 36 in thesupport plates 34. This enables mainstream smoke generated by a lightedtobacco rod 12 to pass into the filter assembly through the canister 18.Smoke passes through openings 36 in the support plates 34 and alsothrough the perforated end walls 26, 28 and through the active medium20. The flaps 38 articulate about the live hinge line 40 upon theapplication of draw to cigarette 10 but once such draw is terminated bythe smoker the flaps return to their normally closed positions. Thisoverall arrangement maintains the freshness and activity level of theactive medium 20 which is only exposed to the atmosphere and mainstreamtobacco smoke when the cigarette is puffed by the smoker.

[0024] Support structure in the form of radiating members 50 is providedfor holding the various elements of canister 18 in place. The supportstructure also functions to space these components in the positionsshown in FIGS. 2 and 4.

[0025]FIG. 6 illustrates a slightly different embodiment of the canister18 where a slightly different form and arrangement of support structure50′ is utilized. Otherwise, the arrangement and function of theembodiment of FIG. 6 is identical to that shown in FIGS. 2-5, andsimilar reference characters have been used to identify similar parts.

[0026] Any number of different active mediums 18 may be placed withincompartment 24 of canister 18. By way of example, activated carbon maybe used for removing selected constituents from the mainstream tobaccosmoke generated by tobacco rod 12. Alternatively, or additionally, aflavorant within compartment 24 may be used for imparting a particularflavor to the mainstream tobacco smoke as such smoke passes through thecanister.

I claim:
 1. A cigarette comprising a tobacco rod and a filter assemblyincluding an impervious canister at least partially filled with anactive medium for modifying the characteristics of tobacco smoke, andvalve structures on opposite ends of the canister each having a normallyclosed condition for sealing the active medium within the imperviouscanister, and the valve structures each having an opened condition uponapplication of draw on the cigarette whereby mainstream smoke generatedby the tobacco rod when lighted passes through the value structures andthe active medium within the canister.
 2. A cigarette as in claim 1wherein each valve structures each comprise a reed valve having anormally closed condition.
 3. A cigarette as in claim 1 wherein theactive medium comprises activated carbon for removing selectedconstituents from mainstream tobacco smoke. 4 A cigarette as in claim 1wherein the active medium comprises a flavorant for imparting flavor tomainstream tobacco smoke.
 5. A cigarette as in claim 1 wherein theactive medium comprises activated carbon for removing selectedconstituents from mainstream tobacco smoke and a flavorant for impartingflavor to mainstream tobacco smoke.